1. Carbon Spring Steel
- Representative grades: 65Mn, 70#, T8A
Carbon spring steel generally has a carbon content of 0.61%-0.90%. Based on its manganese content, it is categorized into two types: those with a standard manganese content of 0.50%-0.80%, such as 65/70/85, and those with a higher manganese content of 0.90%-1.20%, such as 65Mn.

2. Alloy Spring Steel
55CrSi / 60Si2Mn
Features: Silicon addition enhances elasticity and fatigue resistance; provides excellent thermal stability and resistance to tempering softening.
50CrVA (Chrome Vanadium Steel)
Features: High strength, high toughness, excellent fatigue resistance, good resilience, and heat resistance.

Alloy spring steel is a steel that is made by adding one or more alloying elements to carbon spring steel to improve its mechanical properties, hardenability and other properties, so as to meet the performance requirements of various springs.

High-carbon steel generally refers to steel with a carbon content greater than 0.6%. While heat treatment can achieve high hardness, it also results in increased brittleness.
High-strength steel has high comprehensive performance, not just high hardness. Generally, high-strength steel is alloy steel, which is steel with other metal elements added, such as manganese, chromium, nickel, etc., which can greatly improve the overall strength of the steel.

Advantages of Hot-Rolled Steel Plate: Hot-rolled steel can effectively eliminate defects, such as grain refinement. Furthermore, bubbles and cracks generated during casting can be treated at high temperatures and then welded together, avoiding these issues.

Disadvantages of Hot-Rolled Steel Plate: After hot rolling, any non-metallic materials within the steel are compressed into thin sheets, causing delamination, which can affect quality and cause unnecessary problems.

Advantages of Cold-Rolled Steel Plate: It allows for greater deformation of the steel, raising its yield point. Furthermore, the forming speed is relatively fast, resulting in higher production yields without damaging the coating.

Disadvantages of Cold-Rolled Steel Plate: During the forming process, stresses are generated in the cross-section, causing changes in the steel's properties. Furthermore, the wall thickness of cold-rolled steel is relatively small, and subsequent processing does not increase the thickness, resulting in a reduced load-bearing capacity.